Abstract

BackgroundMechanisms of acquired protection to malaria in asymptomatic Plasmodium falciparum carriers are only partially understood. Among them, the role plays by the self-reactive antibodies has not been clarified yet. In this study, the relationship between repertoires of circulating self-reactive and parasite-specific immunoglobulin G (IgG), their correlation with cytokine levels, and their association with protection against malaria was investigated in asymptomatic Plasmodium falciparum-infected Gabonese children.MethodsThe diversity of P. falciparum-specific antibody repertoire was analysed using a protein micro-array immunoassay, the total auto-antibody repertoire by quantitative immunoblotting and circulating cytokine levels were measured by ELISA in endemic controls (EC) and P. falciparum-infected children from Gabon with asymptomatic (AM) or mild malaria (MM). The association of self- and parasite-specific antibody repertoires with circulating cytokines was evaluated using single linkage hierarchical clustering, Kruskal – Wallis tests and Spearman’s rank correlation.ResultsChildren with AM exhibited an IgG response to merozoite surface protein 3 (MSP3) but not to MSP1-19, although their levels of total P. falciparum-specific IgG were similar to those in the MM group. Moreover, the asymptomatic children had increased levels of autoantibodies recognising brain antigens. In addition, a correlation between IL-10 levels and parasite load was found in AM and MM children. These two groups also exhibited significant correlations between plasma levels of IL-10 and IFN-γ with age and with total plasma IgG levels. IL-10 and IFN-γ levels were also associated with auto-antibody responses in AM.ConclusionsAltogether, these results indicate that a self-reactive polyclonal response associated with increased IgG to MSP3 and high plasma levels of IL-10 and IFN-γ may contribute to protective immune mechanisms triggered in asymptomatic P. falciparum infection in Gabonese children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-0658-7) contains supplementary material, which is available to authorized users.

Highlights

  • Mechanisms of acquired protection to malaria in asymptomatic Plasmodium falciparum carriers are only partially understood

  • These results strongly support a protective role for auto-antibodies triggered by the parasite which correlate with plasma IL-10 levels and with anti-MSP2 and anti-merozoite surface protein 3 (MSP3) immunoglobulin G (IgG) levels in clinical immunity observed in asymptomatic P. falciparum carriers

  • Individuals with positive P. falciparum thin blood smears and no clinical symptoms were included in the asymptomatic malaria (AM) group and were defined as AM carriers and children with no clinical symptoms and a negative thin blood smears were enrolled in the endemic control (EC) group

Read more

Summary

Introduction

Mechanisms of acquired protection to malaria in asymptomatic Plasmodium falciparum carriers are only partially understood. The relationship between repertoires of circulating self-reactive and parasite-specific immunoglobulin G (IgG), their correlation with cytokine levels, and their association with protection against malaria was investigated in asymptomatic Plasmodium falciparum-infected Gabonese children. Plasmodium falciparum infection can lead to asymptomatic malaria (AM), mild malaria (MM) or severe malaria (SM) [1]. The mechanisms of naturally acquired immunity to malaria are only partially understood. Antibody-mediated effector mechanisms are implicated in protective immunity [3,4,5]. This protection is against severe disease, not re-infection. There is still a need to identify immune response components of clinical immunity

Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call